tools/nolibc: add support for 32-bit parisc

Extend nolibc to target the 32-bit parisc architecture.
64-bit is not yet supported.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch/msgid.link/20260428-nolibc-hppa-v5-2-d843d573111a@weissschuh.net

3 files changed, 188 insertions, 1 deletions

diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
index 2cb4d610fe53..00fd2e566d75 100644
--- a/tools/include/nolibc/Makefile
+++ b/tools/include/nolibc/Makefile
@@ -17,7 +17,7 @@ endif
 # it defaults to this nolibc directory.
 OUTPUT ?= $(CURDIR)/
 
-architectures := arm arm64 loongarch m68k mips openrisc powerpc riscv s390 sh sparc x86
+architectures := arm arm64 loongarch m68k mips openrisc parisc powerpc riscv s390 sh sparc x86
 arch_files := arch.h $(addsuffix .h, $(addprefix arch-, $(architectures)))
 all_files := \
 		alloca.h \
diff --git a/tools/include/nolibc/arch-parisc.h b/tools/include/nolibc/arch-parisc.h
new file mode 100644
index 000000000000..417043ecbc53
--- /dev/null
+++ b/tools/include/nolibc/arch-parisc.h
@@ -0,0 +1,185 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * parisc/hppa (32-bit) specific definitions for NOLIBC
+ * Copyright (C) 2026 Thomas Weißschuh <linux@weissschuh.net>
+ */
+
+#ifndef _NOLIBC_ARCH_PARISC_H
+#define _NOLIBC_ARCH_PARISC_H
+
+#if defined(__LP64__)
+#error 64-bit not supported
+#endif
+
+#include "compiler.h"
+#include "crt.h"
+
+/* Syscalls for parisc :
+ *   - syscall number is passed in r20
+ *   - arguments are in r26 to r21
+ *   - the system call is performed by calling "ble 0x100(%sr2, %r0)",
+ *     the instruction after that is in the delay slot and executed before
+ *     the jump to 0x100 actually happens, use it to load the syscall number
+ *   - syscall return comes in r28
+ *   - the arguments are cast to long and assigned into the target
+ *     registers which are then simply passed as registers to the asm code,
+ *     so that we don't have to experience issues with register constraints.
+ */
+
+#define _NOLIBC_SYSCALL_CLOBBERLIST \
+	"memory", "%r1", "%r2", "%r4", "%r20", "%r29", "%r31"
+
+#define __nolibc_syscall0(num)                                                \
+({                                                                            \
+	register long _ret __asm__ ("r28");                                   \
+									      \
+	__asm__ volatile (                                                    \
+		"ble 0x100(%%sr2, %%r0)\n\t"                                  \
+		"copy %1, %%r20\n\t"                                          \
+		: "=r"(_ret)                                                  \
+		: "r"(num)                                                    \
+		: _NOLIBC_SYSCALL_CLOBBERLIST,                                \
+		  "%r21", "%r22", "%r23", "%r24", "%r25", "%r26"              \
+	);                                                                    \
+	_ret;                                                                 \
+})
+
+#define __nolibc_syscall1(num, arg1)                                          \
+({                                                                            \
+	register long _ret __asm__ ("r28");                                   \
+	register long _arg1 __asm__ ("r26") = (long)(arg1);		      \
+									      \
+	__asm__ volatile (                                                    \
+		"ble 0x100(%%sr2, %%r0)\n\t"                                  \
+		"copy %2, %%r20\n\t"                                          \
+		: "=r"(_ret),                                                 \
+		  "+r"(_arg1)                                                 \
+		: "r"(num)                                                    \
+		: _NOLIBC_SYSCALL_CLOBBERLIST,                                \
+		  "%r21", "%r22", "%r23", "%r24", "%r25"                      \
+	);                                                                    \
+	_ret;                                                                 \
+})
+
+#define __nolibc_syscall2(num, arg1, arg2)                                    \
+({                                                                            \
+	register long _ret __asm__ ("r28");                                   \
+	register long _arg1 __asm__ ("r26") = (long)(arg1);		      \
+	register long _arg2 __asm__ ("r25") = (long)(arg2);		      \
+									      \
+	__asm__ volatile (                                                    \
+		"ble 0x100(%%sr2, %%r0)\n\t"                                  \
+		"copy %3, %%r20\n\t"                                          \
+		: "=r"(_ret),                                                 \
+		  "+r"(_arg1), "+r"(_arg2)                                    \
+		: "r"(num)                                                    \
+		: _NOLIBC_SYSCALL_CLOBBERLIST,                                \
+		  "%r21", "%r22", "%r23", "%r24"                              \
+	);                                                                    \
+	_ret;                                                                 \
+})
+
+#define __nolibc_syscall3(num, arg1, arg2, arg3)                              \
+({                                                                            \
+	register long _ret __asm__ ("r28");                                   \
+	register long _arg1 __asm__ ("r26") = (long)(arg1);		      \
+	register long _arg2 __asm__ ("r25") = (long)(arg2);		      \
+	register long _arg3 __asm__ ("r24") = (long)(arg3);		      \
+									      \
+	__asm__ volatile (                                                    \
+		"ble 0x100(%%sr2, %%r0)\n\t"                                  \
+		"copy %4, %%r20\n\t"                                          \
+		: "=r"(_ret),                                                 \
+		  "+r"(_arg1), "+r"(_arg2), "+r"(_arg3)                       \
+		: "r"(num)                                                    \
+		: _NOLIBC_SYSCALL_CLOBBERLIST,                                \
+		  "%r21", "%r22", "%r23"                                      \
+	);                                                                    \
+	_ret;                                                                 \
+})
+
+#define __nolibc_syscall4(num, arg1, arg2, arg3, arg4)                        \
+({                                                                            \
+	register long _ret __asm__ ("r28");                                   \
+	register long _arg1 __asm__ ("r26") = (long)(arg1);		      \
+	register long _arg2 __asm__ ("r25") = (long)(arg2);		      \
+	register long _arg3 __asm__ ("r24") = (long)(arg3);		      \
+	register long _arg4 __asm__ ("r23") = (long)(arg4);		      \
+									      \
+	__asm__ volatile (                                                    \
+		"ble 0x100(%%sr2, %%r0)\n\t"                                  \
+		"copy %5, %%r20\n\t"                                          \
+		: "=r"(_ret),                                                 \
+		  "+r"(_arg1), "+r"(_arg2), "+r"(_arg3), "+r"(_arg4)          \
+		: "r"(num)                                                    \
+		: _NOLIBC_SYSCALL_CLOBBERLIST,                                \
+		  "%r21", "%r22"                                              \
+	);                                                                    \
+	_ret;                                                                 \
+})
+
+#define __nolibc_syscall5(num, arg1, arg2, arg3, arg4, arg5)                  \
+({                                                                            \
+	register long _ret __asm__ ("r28");                                   \
+	register long _arg1 __asm__ ("r26") = (long)(arg1);		      \
+	register long _arg2 __asm__ ("r25") = (long)(arg2);		      \
+	register long _arg3 __asm__ ("r24") = (long)(arg3);		      \
+	register long _arg4 __asm__ ("r23") = (long)(arg4);		      \
+	register long _arg5 __asm__ ("r22") = (long)(arg5);		      \
+									      \
+	__asm__ volatile (                                                    \
+		"ble 0x100(%%sr2, %%r0)\n\t"                                  \
+		"copy %6, %%r20\n\t"                                          \
+		: "=r"(_ret),                                                 \
+		  "+r"(_arg1), "+r"(_arg2), "+r"(_arg3), "+r"(_arg4),         \
+		  "+r"(_arg5)                                                 \
+		: "r"(num)                                                    \
+		: _NOLIBC_SYSCALL_CLOBBERLIST,                                \
+		  "%r21"                                                      \
+	);                                                                    \
+	_ret;                                                                 \
+})
+
+#define __nolibc_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6)            \
+({                                                                            \
+	register long _ret __asm__ ("r28");                                   \
+	register long _arg1 __asm__ ("r26") = (long)(arg1);		      \
+	register long _arg2 __asm__ ("r25") = (long)(arg2);		      \
+	register long _arg3 __asm__ ("r24") = (long)(arg3);		      \
+	register long _arg4 __asm__ ("r23") = (long)(arg4);		      \
+	register long _arg5 __asm__ ("r22") = (long)(arg5);		      \
+	register long _arg6 __asm__ ("r21") = (long)(arg6);		      \
+									      \
+	__asm__ volatile (                                                    \
+		"ble 0x100(%%sr2, %%r0)\n\t"                                  \
+		"copy %7, %%r20\n\t"                                          \
+		: "=r"(_ret),                                                 \
+		  "+r"(_arg1), "+r"(_arg2), "+r"(_arg3), "+r"(_arg4),         \
+		  "+r"(_arg5), "+r"(_arg6)                                    \
+		: "r"(num)                                                    \
+		: _NOLIBC_SYSCALL_CLOBBERLIST                                 \
+	);                                                                    \
+	_ret;                                                                 \
+})
+
+#ifndef NOLIBC_NO_RUNTIME
+/* startup code */
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __nolibc_no_stack_protector _start(void)
+{
+	__asm__ volatile (
+		".import $global$\n"           /* Set up the dp register */
+		"ldil L%$global$, %dp\n"
+		"ldo R%$global$(%r27), %dp\n"
+
+		"b _start_c\n"                 /* Call _start_c, the load below is executed first */
+
+		"ldo -4(%r24), %r26\n"         /* The sp register is special on parisc.
+						* r24 points to argv. Subtract 4 to get &argc.
+						* Pass that as first argument to _start_c.
+						*/
+	);
+	__nolibc_entrypoint_epilogue();
+}
+#endif /* NOLIBC_NO_RUNTIME */
+
+#endif /* _NOLIBC_ARCH_PARISC_H */
diff --git a/tools/include/nolibc/arch.h b/tools/include/nolibc/arch.h
index 55009dcafe9e..b69d9c5ec5c6 100644
--- a/tools/include/nolibc/arch.h
+++ b/tools/include/nolibc/arch.h
@@ -30,6 +30,8 @@
 #include "arch-sh.h"
 #elif defined(__or1k__)
 #include "arch-openrisc.h"
+#elif defined(__hppa__)
+#include "arch-parisc.h"
 #else
 #error Unsupported Architecture
 #endif